EP3644449A1

EP3644449A1 - Connection assembly, female contact and connection method

Info

Publication number: EP3644449A1
Application number: EP19205187.8A
Authority: EP
Inventors: François CORMIER; Soizic LE GLOUANEC; Sylvain Bossuyt
Original assignee: Aptiv Technologies Ltd
Current assignee: Aptiv Technologies AG
Priority date: 2018-10-26
Filing date: 2019-10-24
Publication date: 2020-04-29
Anticipated expiration: 2039-10-24
Also published as: EP3644449B1; FR3087955A1; FR3087955B1; US10916873B2; KR20200049597A; CN111106495A; US20200136287A1; KR102299831B1; CN111106495B

Abstract

In a connection assembly comprising a male contact and a female contact (301), the female contact (301) comprises a plurality of elastic blades (308) extending longitudinally along a central axis (C) parallel to a direction of insertion. Each of these blades (308) comprises two bent contact zones to form, respectively, on each of these bent zones, a first and a second contact surfaces that are convex and essentially oriented towards the central axis (C), the first contact surface being situated closer than the second contact surface to the free end (309) of the blade (308) on which they are formed.

Description

The invention relates to the field of power connection systems for motor vehicles. For example, the invention can find an application in a power connector, such as those used to charge a rechargeable electric or hybrid vehicle battery.
Thus, for example, as represented schematically in Fig. 1, the rechargeable electric or hybrid vehicles 100 can comprise a connector socket 200 to which can be connected a charge plug 300 powered by an electric charging station 400, via a cable 500. This charge plug 300 then makes it possible to charge a battery located in the vehicle 100.
A charge plug 300 generally comprises power electrical contacts 301 for the charging of the vehicle (an example of power electrical contacts is described for example in the document WO2017195013A1 ) and electrical contacts 302 intended to transmit an electrical signal (see for example the exploded view of the charge plug represented in Figure 2B). The power electrical contacts 301 for the charging of the vehicle are female contacts. This electrical signal generally makes it possible to control the power supply of the charge plug 300, in particular during connection and disconnection phases, so as to cut the power supply before the charge plug 300 is itself fully disconnected. It can however happen that, in rare circumstances, a charge plug 300 is disconnected while it is powered. In such circumstances, an electrical arc can occur between the power contacts 301 of the charge plug 300 and the power contacts of the socket 200. It has been observed that such electrical arcs can damage, in particular, the power contacts 301 of the charge plug 300. It is then desirable to avoid having the contact quality at the power contacts 301 being degraded if the charge plug is disconnected while it is powered. For example, it is desirable to ensure a constant contact quality even if the charge plug 300 undergoes at least fifty live disconnections.
In the field of power connection systems for motor vehicles, the female contacts for the charge plugs are generally machined by bar turning from a bar of conductive material, for example a copper alloy. Such a female contact comprises a bush comprising a plurality of elastic blades. Each elastic blade extends longitudinally, parallel to a central axis, between a base and a free end. The generation of an insertion force, of a contact force and of an electrical conduction suited to the application targeted is obtained in particular by the choice of the material and of the form of the blades (cross section, length, angle relative to the central axis, etc.). These blades are configured to receive the pin of a male contact between them when the latter is mated to the female contact. Each blade is thus configured to establish at least one electrical contact with the pin of the male contact.
The applicant is faced by a problem of designing and producing a female contact that can retain a constant contact quality even if the charge plug undergoes at least fifty live disconnections.
The solution found consists in creating, on the female contacts, in the present case mounted in a charge plug, at least two contact zones: a sacrificial zone at which an electrical arc can occur and a useful contact zone which is preserved from any electrical arcs. More specifically, in order to ensure that no electrical arc can occur at a useful contact zone, each blade is provided with a sacrificial zone.
There is thus provided, according to the invention, a connection assembly comprising a male contact and a female contact. The male contact comprises a pin composed of an electrically conductive material. This pin extends longitudinally along a central axis parallel to a direction of insertion (during the coupling of the male contact with a female contact or when the latter are mated), between an end linked mechanically and electrically to a fixing portion, and a free end. The female contact comprises a bush comprising a plurality of elastic blades. Each elastic blade extends longitudinally, between a base and a free end. In other words, each blade is linked to the rest of the contact only at the base. The blades are configured to receive the pin of the male contact between them and establish at least one electrical contact with the pin, when the male contact is mated to the female contact.
Furthermore, each of the blades comprises two bent contact zones so as to form, respectively, on each of these bent zones, a first and a second contact surfaces that are convex and essentially oriented towards the central axis, the first contact surface being situated closer than the second contact surface to the free end of the blade on which they are formed. In other words, the first contact surface corresponds to a sacrificial zone and the second contact surface corresponds to a useful contact zone.
Furthermore, the pin is provided, at its free end, with a cap composed of a dielectric material. The first contact surface of each blade is then conformed so that, upon connection of the male contact and of the female contact, the first contact surface rests on the cap before establishing an electrical contact with an electrically conductive zone of the pin.
This connection assembly possibly comprises one or other of the following features, considered independently of one another or in combination with one or more others:

upon the introduction of the male contact between the blades, the first and second contact surfaces rest in succession on the outer surface of the cap, inclined relative to the direction of insertion;
the bush is formed by cutting and stamping of an electrically conductive material in sheet form;
each of the two contact zones is conformed so that, upon the disconnection of the male contact and of the female contact, there is a respective position of the male and female contacts in which the first contact surface is still in contact with the pin, while the second contact surface is no longer in contact with the pin and is located in line with the cap;
the pin and the cap have essentially a symmetry of revolution about the central axis;
the cap has an essentially tapered form, the height of which is located on the central axis, and the two contact surfaces of each blade are conformed so that, upon the disconnection of the male contact and of the female contact, the second contact surface rests temporarily on the cap while the first contact surface is still in contact with the pin;
the first contact surface of each blade is in contact with the pin when the male and female contacts are mated; alternatively, the first contact surface of each blade is not in contact with the pin when the male and female contacts are mated;
each blade comprises a section at right angles to the longitudinal direction, essentially rectangular, between the base and its free end;
each of the blades comprises a third bent zone, concave relative to the reception space, this third zone being situated between the first and second bent contact zones;
when the blades are not stressed and they are considered from their second contact surface to the base, the blades form an acute angle with the direction of insertion;
when the blades are not stressed and they are considered from their first contact surface to their free end, the blades form an acute angle with the direction of insertion;
the length of the cap parallel to the direction of insertion is greater than or equal to the distance between the first and second contact surfaces parallel to this same direction.

According to another aspect, the invention relates to a female contact for a connection assembly as mentioned above.
According to yet another aspect, the invention relates to a connection, disconnection and electrical power supply method for an assembly such as that mentioned above. This method comprises:

a power supply phase during which the male contact and the female contact are passed through by a current greater than or equal to 32 amperes while the second contact surfaces establish a physical and electrical contact with the pin, and the first contact surfaces are not in physical and electrical contact with the pin, and
a phase of disconnection of the male and female contacts, in which at least one first contact surface remains in electrical contact with the pin, while each first contact surface is at a distance from any conductive zone of the pin of at least 1.5 millimetres.

Other features and advantages of the invention will become apparent on reading the following detailed description and from the attached drawings. In these drawings:

Figure 1 represents, schematically and in perspective, a connection assembly according to the invention, with a socket mounted on a vehicle and a charge plug mounted on a cable and connected to the socket;
Figure 2 represents, schematically and in perspective, an example of charge plug such as that shown in Figure 1;
Figure 3 represents, schematically and in perspective, a female contact according to a first embodiment of the invention;
Figure 4 represents, schematically, in longitudinal cross section and in perspective, the female contact of Figure 3;
Figure 5 represents, schematically in cross section, the female contact of Figures 3 and 4,
Figure 6 represents, schematically and in longitudinal cross section, a detail of the female contact of Figures 3 to 5,
Figure 7 represents, schematically and in longitudinal cross section, the blades of a second embodiment of a female contact according to the invention,
Figures 8A to 8D represent, schematically, different phases of a connection method for a male contact and a female contact according to the second embodiment of a connection assembly according to the invention, and
Figures 9A to 9D represent, schematically, different phases of a disconnection method for a male contact and a female contact according to the second embodiment of a connection assembly according to the invention.

An example of connection assembly according to the invention is represented in Figure 1. This assembly comprises a connector socket 200 and a charge plug 300. Male power contacts 201 (not represented in Figure 1) are mounted in cells of the socket 200. The male contacts 201 comprise a pin 202 composed of an electrically conductive material and extending longitudinally along a central axis C parallel to a direction of insertion, between an end linked mechanically and electrically to a fixing portion, and a free end. They are of a type known to the person skilled in the art. Power female contacts 301 are mounted in the charge plug 300.
As represented in Figure 2, the charge plug 300 comprises a housing 303 (in the present case composed of several elements 303a) in which are housed, in a manner known to the person skilled in the art, female contacts 301. As represented in Figures 3 and 4, the female contacts 301 comprise a fixing portion 304 and a connection portion 305. The fixing portion 304 is intended to electrically and mechanically link the contact 301 to an electrical wire. The connection portion 305 is intended to receive a pin 202 of a male contact 201.
The female contact 301 corresponding to the embodiment of Figures 3 to 6, is formed by cutting and stamping an electrically conductive material in sheet form. This material is composed for example of a copper alloy, in the form of a sheet whose thickness is between 0.3 and 1 millimetre, and is for example preferentially 0.6 millimetres.
This female contact 301 is designed to comply with the international standard IEC 62196. The latter defines the interface between the charge plug 300 and the socket 200, the geometry of the cavities in which the contacts must be housed and the points at which the electrical conduction must be established between the male and female contacts.
Thus, for example, the female contact 301 must make it possible to maintain a heating temperature lower than 50°C when, mated with a male contact 201, it is passed through by an electrical current of 44 amperes. However, even if, for this purpose, a relatively thick sheet of electrically conductive material is used, the coupling effort between the female contact 301 and a male contact 201 must be less than 5 Newtons.
Furthermore, this female contact 301 must satisfy

a wear test over at least 14 000 coupling/uncoupling cycles with a male contact 201, and
50 disconnections under load without it being possible to observe a heating greater than that indicated above.

To these constraints is added the fact that the male 201 and female 301 contacts must comply with the IP2X standard, and possibly that the cost of production of the female contacts 301 be controlled, even reduced.
All this has been taken into account in designing the female contact 301 described hereinbelow.
The fixing portion 304 is designed to produce a fixing and connection by clamping with an electrical wire. In Figures 3 and 4, the fixing portion 304 is still linked to a support strip 306.
After cutting and shaping, the female contact 301 has a connection portion 305 in the form of an essentially cylindrical bush. The bush is formed by bending and rolling the sheet of cut electrically conductive material. The connection portion 305 is linked mechanically to the fixing portion 304. This bush comprises a base 307 and a plurality of elastic blades 308. In the example represented, there are six of the elastic blades 308, distributed essentially symmetrically about a central axis C, parallel to a direction of insertion of a pin 202 of a male contact 201 into the bush. Each elastic blade 308 extends longitudinally, between the base 307 and a free end 309. Each elastic blade 308 is linked to the rest of the contact only at the base 307. In other words, each blade 308 is separated from its nearest neighbours by a space 310 which extends between the base 307 and the free end 309 of the blades 308 and which mechanically and electrically insulates them from one another. Between the base 307 and the free end 309 of the blades 308, the cross section of the blades 308 is essentially rectangular (see also Figure 5).
The base 307 essentially has a straight circular cylindrical form. The longitudinal edges 311 of the cutout at the base meet on a plane of symmetry P (cutting plane of Figure 4, see also Figure 5), passing also through two diametrically opposing gaps 310. The blades 308 are distributed symmetrically on either side of this plane of symmetry P (three blades 308 on each side of the plane).
As represented in Figure 4, each elastic blade 308 comprises a first portion 312 situated in the extension of the base 307 and parallel to the generatrix of the cylinder of the base 307. For example, this first portion 312 has a length of between 3 and 10 millimetres, and is for example preferentially 5 millimetres.
Each elastic blade 308 also comprises a second portion 313 situated in the extension of the first portion 312 towards the free end 309. When it is not stressed, the second portion 313 forms, with the first portion 312 (that is to say also with the central axis C) an angle α of between 2 degrees and 15 degrees, and is for example preferentially 8 degrees. In other words, when the blades 308 are not stressed and they are considered from their second contact surface 314 to the base 307, the blades form an acute angle α with the direction of insertion.
For example, this second portion 313 has a length of between 25 and 35 millimetres, and is for example preferentially 21 millimetres. The join between the first 312 and second 313 portions acts as hinge. In other words, when the pin 202 of a male contact 201 is inserted between the blades 308 of a female contact 301, the length of the second portion 313 is such that the second portion 313 forms a lever which is deformed essentially at the join between the first 312 and second 313 portions. This lever makes it possible to control the insert effort.
Each elastic blade 308 also comprises a third portion 315 situated in the extension of the second portion 313 towards the free end 309. The third portion 315 comprises two bent contact zones 316. These bent zones 316 comprise, each respectively, on the inner face of the corresponding blade 308, a first 317 and a second 314 contact surfaces.
The lever provided by the second portion 313 thus makes it possible to control the contact force at these first 317 and second 314 contact surfaces.
When a blade 308 is not stressed, the third portion 316 forms, with the direction of insertion, a general angle β of between 5 and 20 degrees, and is for example preferentially 15 degrees. In other words, when the blades 308 are not stressed and they are considered from their first contact surface 317 to their free end 309, the blades form an acute angle β with the direction of insertion.
Each of these contact surfaces 314, 317 is convex and essentially oriented towards the space of reception of the pin 202 of a male contact 201 between the blades 308. In other words, the curvature of this surface is generally directed towards the central axis C. The first contact surface 317 corresponds to a sacrificial contact zone to which any electrical arc is wanted to be oriented and which can possibly be degraded. In other words, the contact resistance can increase at a point of contact between this first contact surface 317 and the pin 202 of a male contact 201. The second contact surface 314 corresponds to a useful contact zone for which the contact quality is wanted to be preserved. In other words, there is a desire to avoid having the contact resistance increase at a point of contact between this second contact surface 314 and the pin 202 of a male contact 201.
More specifically, each blade 308 is bent towards the central axis C at the join between the second 313 and third 315 portions, to form a useful contact zone (at the second contact surface 314) which approaches the central axis C. Then, each blade 308 has an inclined surface relative to the direction of insertion intended to limit the insertion effort, while leaving sufficient length towards the free end 309 to produce a sacrificial contact zone. In continuing along each blade 308, towards its free end 309, each blade 308 is once again curved, towards the central axis C, over a zone 318 which corresponds therefore in cross section to a concave form relative to the reception space. This concave zone 318 extends to the sacrificial contact zone (at the first contact contact surface 317) which has a curvature which corresponds in cross section to a convex form relative to the reception space. Finally, the sacrificial contact zone is extended towards the free end by a part 319 that is essentially rectilinear seen in cross section.
A second embodiment of a female contact according to the invention is represented in Figure 7. The latter also comprises a fixing portion and a connection portion, but only the second 313 and third 315 portions of the connection portion 305 are represented. Each blade 308 comprises, as for the preceding embodiment, a first 317 and a second 314 contact surfaces. The first contact surface 317 corresponds to a sacrificial contact zone and the second contact surface 314 corresponds to a useful contact zone.
In this embodiment, each blade 308 is curved away from the central axis C at the join between the second 313 and third 315 portions, in order to have, upon the insertion of the male contact 201 between the blades 308, an inclined surface relative to the direction of insertion intended to limit the insertion effort, while leaving sufficient length towards the free end 309 to produce a sacrificial contact zone. Then, the blade is curved in the opposite direction (over a zone 320 which corresponds therefore in cross section to a concave form relative to the reception space). After this zone 320 having a concave curvature, in the direction of the free end 309 of the blades 308, each blade 308 is continued by a straight portion 321 that is inclined towards the axis of insertion. This straight portion 321 is continued to the sacrificial contact zone (at the first contact surface 317) which has a curvature which corresponds in cross section to a convex form relative to the reception space. Finally, the sacrificial contact zone is extended, in the direction of the free end 309, by a part 322, seen in cross section, that is essentially rectilinear moving away from the central axis. This rectilinear part 322 forms, relative to the direction of insertion, essentially the same angle as the portion following the useful contact zone. This angle is designed to limit the effort of insertion of the pin of the male contact between the blades.
This second embodiment of the female contact is used, in relation to Figures 8A to 8D and 9A to 9D, to illustrate an example of connection and disconnection method according to the invention.
Figure 8A (position equivalent to that of Figure 9D): a male contact 201 is introduced between the blades 308, into the reception space, at their free end 309. The blades 308 are not yet stressed and only a part of the cap 203 made of electrically insulating material of the male contact 201 penetrates at the third portion 315. The cap 203 has a tapered form and the first contact surface 317 rests on the outer surface (inclined relative to the direction of insertion) of the cap 203.
Figure 8B (position equivalent to that of Figure 9C): the pin 202 of the male contact 201 is introduced even more between the blades 308, in the reception space. The blades 308 are stressed and begin to be deformed. The first contact surface 317 rests on the conductive part of the pin 202. The second contact surface 314 is located in line with the cap, but does not rest on it.
Figure 8C (position equivalent to that of Figure 9B): the pin 202 of the male contact 201 is introduced even more between the blades 308, in the reception space. The first contact surface 317 rests on the conductive part of the pin 202. The blades 308 are a little more stressed and deformed. The second contact surface 314 is located in line with the cap and rests on the inclined surface thereof.
Figures 8D and 9A: the pin 202 of the male contact 201 is introduced between the blades 308, in the reception space. The blades 308 are stressed and deformed to the maximum. The second contact surface 314 rests on the conductive pin 202, while the first contact surface 317 no longer rests thereon. The connection assembly comprising the male contact 201 and the female contact 301 can be passed through by a current. The electrical contact is established between the second contact surface 314 and the conductive part of the pin 202. The second contact surface 314 represents a useful contact surface safeguarded from any electrical arcs, at which the heating cannot exceed, for a given current, a limit that is predetermined by design.
Figure 9B: on disconnection, the pin 202 of the male contact 201 leaves the reception space but, in this step, even though the second contact surface 314 is no longer in electrical contact with the conductive part of the pin 202, the first contact surface 317 does still rest thereon. The second contact surface 314 is located in line with the cap and rests on the inclined surface thereof. An electrical arc cannot therefore occur because there is sufficient conduction at the first contact surface 317.
Figure 9C: the pin 202 of the male contact 201 is still in contact with the first contact surface 317. The second contact surface 314 is located in line with the cap and no longer rests on the inclined surface thereof. An electrical arc cannot occur because there is sufficient conduction at the first contact surface 317. There is therefore a respective position of the male 201 and female 301 contacts in which the first contact surface 317 is still in contact with the pin 202, while the second contact surface 314 is no longer in contact with the pin 202 and is located in line with the cap 203. In other words, the length of the cap parallel to the direction of insertion is greater than or equal to the distance between the first 317 and second 314 contact surfaces parallel to this same direction.
Figure 9D: the first 317 and second 314 contact surfaces are no longer directly in electrical contact with the conductive part of the pin 202. If an electrical arc occurs, it will be established between the first contact surface 317 and the conductive part of the pin 202 since they correspond to the conductive zones closest to one another.
Generally, it can be noted that the production of female contacts 301 by cutting and stamping an electrically conductive material (rather than by turning/bar turning) facilitates the production of more complex forms of blades 308, and in particular the production of multiple contact zones or surfaces 314, 317, with a geometry that is accurate and suited to the production of a sacrificial zone, and of another functional contact zone which will not be damaged by the occurrence of electrical arcs.

Claims

Connection assembly comprising a male contact (201) and a female contact (301);
- the male contact (201) comprising a pin (202) composed of an electrically conductive material and extending longitudinally along a central axis (C) parallel to a direction of insertion, between an end linked mechanically and electrically to a fixing portion, and a free end,

- the female contact (301) comprising a bush comprising a plurality of elastic blades (308), each blade (308) extending longitudinally, between a base (307) and a free end (309), and being linked to the rest of the contact (301) only at the base (307), these blades (308) being configured to receive the pin (202) of the male contact (201) between them and to establish at least one electrical contact with the pin (202), when the male contact (201) is mated to the female contact (301);
in which
- each of these blades (308) comprises two bent contact zones to form, respectively, on each of these bent contact zones, a first (317) and a second (314) contact surfaces that are convex and essentially oriented towards the central axis (C), the first contact surface (317) being situated closer than the second contact surface (314) to the free end (309) of the blade (308) on which they are formed,

- the pin (202) is provided at its free end with a cap (203) composed of a dielectric material,
characterized in that the first contact surface (317) of each blade (308) is conformed so that, upon the connection of the male contact (201) and of the female contact (301), the first contact surface (317) rests on the cap (203) before establishing an electrical contact with an electrically conductive zone of the pin (202).
Connection assembly according to Claim 1, in which, upon the introduction of the male contact (201) between the blades (308), the first (317) and second (314) contact surfaces rest respectively on the outer surface, inclined relative to the direction of insert, of the cap (203).
Connection assembly according to Claim 1 or 2, in which the bush is formed by cutting and stamping an electrically conductive material in sheet form.
Connection assembly according to one of the preceding claims, in which each of the two bent contacts zones is conformed so that, upon the disconnection of the male contact (201) and of the female contact (301), there is a respective position of the male (201) and female (301) contacts in which the first contact surface (317) is still in contact with the pin (202), while the second contact surface (314) is no longer in contact with the pin (202) and is located in line with the cap (203).
Connection assembly according to one of the preceding claims, in which the pin (202) and the cap (203) have essentially a symmetry of revolution about the central axis (C).
Connection assembly according to one of the preceding claims, in which the cap (203) has an essentially tapered form, the height of which is located on the central axis, and the two contact surfaces (314, 317) of each blade (308) are conformed so that, upon the disconnection of the male contact (201) and of the female contact (301), the second contact surface (314) rests temporarily on the cap (203) while the first contact surface (317) is still in contact with the pin (202).
Connection assembly according to one of the preceding claims, in which the first contact surface (317) of each blade (308) is in contact with the pin (202) when the male (201) and female (301) contacts are mated.
Connection assembly according to one of Claims 1 to 6, in which the first contact surface (317) of each blade (308) is not in contact with the pin (202) when the male (201) and female (301) contacts are mated.
Connection assembly according to one of the preceding claims, in which each blade (308) comprises a section at right angles to the longitudinal direction, essentially rectangular, between the base (307) and its free end (309).
Connection assembly according to one of the preceding claims, comprising a third bent zone (318), concave relative to the reception space, this third zone (318) being situated between the first (317) and second (314) bent contact zones.
Connection assembly according to one of the preceding claims, in which, when the blades (308) are not stressed and they are considered from their second contact surface (314) to the base (307), the blades (308) form an acute angle (α) with the direction of insertion.
Connection assembly according to one of the preceding claims, in which, when the blades (308) are not stressed and they are considered from their first contact surface (317) to their free end (309), the blades (308) form an acute angle (β) with the direction of insertion.
Connection assembly according to one of the preceding claims, in which the length of the cap (203) parallel to the direction of insertion is greater than or equal to the distance between the first (317) and second (314) contact surfaces parallel to this same direction.
Connection, disconnection and electrical power supply method for an assembly according to one of the preceding claims, comprising:
- a power supply phase during which the male contact (201) and the female contact (301) are passed through by a current greater than or equal to 32 amperes while the second contact surfaces (314) establish a physical and electrical contact with the pin (202), and the first contact surfaces (317) are not in physical and electrical contact with the pin (202), and

- a phase of disconnection of the male (201) and female (301) contacts, in which at least one first contact surface (317) remains in electrical contact with the pin (202), while each first contact surface (317) is at a distance from any conductive zone of the pin of at least 1.5 millimetres.
Method according to Claim 14, in which, in the disconnection phase, the male (201) and female (301) contacts pass through a position in which the first contact surface (317) is still in contact with the pin (202), while the second contact surface (314) is no longer in contact with the pin (202) and is located in line with the cap (203).